2 
Development = 2215 : — 
General ... 
Oogenesis and Ovum 
Spermatogenesis and Spermatozoon 
Embryology ... .... 
Ethology = 2219 : — 
General 
Movements, Locomotion 
Enemies, Defence and Protection 
Erosion ... 
Feeding Habits 
Breeding Habits ... 
Behaviour under certain conditions 
Habitat 
Boring and Burrowing Habits 
Acclimatisation, etc. 
Hibernation and ^Estivation 
Parasitism, Commensalism, Parasites, etc. 
Evolution ... 
Luminosity... 
Economics ... 
Variation and JEtiology = 2223 : — 
Teratology, Phylogeny and Relationship 
Evolution 
Distribution = 2227 : — 
General ... ..* 
(a) Recent: — 
(«) Marine : — 
North Atlantic Ocean, Caribbean Sea and 
Gulf of Mexico 
Mediterranean Sea, Black Sea 
South Atlantic Ocean... 
Indian Ocean, Red Sea ... ... ... 
Malaysia 
Pacific Ocean ... 
Southern Ocean 
PAGK 
)>2 2 
J>22 
}23 
23 
r23 
